This invention relates to colorants suitable for use in food products, to food products containing same, and to methods of obtaining the colorants.
Colorants in foods are either natural pigments or synthetic dyes or lakes. Since the number of synthetic colors is limited, there is need to further explore natural pigments as colorants. More specifically, there is extensive research in finding suitable natural red pigments as color additives.
The present invention relates in particular to an anthocyanin colorant obtained by extraction from grape pomace. These anthocyanin colorants are well known, but conventional extraction methods result in products having a generally low color strength.
Daniel Marmion., "Handbook of U.S. Colorants For Foods, Drugs, and Cosmetics," pages 89-90 teaches the extraction of anthocyanin from grape skin extract by the addition of sulfur dioxide during the steeping process. The extract is then concentrated by vacuum evaporation to remove the alcohol formed during fermentation of the extracted sugars. Charobago et al., "Ion Exchange Purified Anthocyanin Pigments As A Colorant For Cranberry Juice Cocktail, "Journal of Food Science, 38, 464-467 teaches the extraction of Anthocyanin with acidified alcohol, then adsorption of the pigment on an ion exchange resin, and elute with an alcohol to recover the pigment. The anthocyanin produced by the above methods are impure, that is, it contains tannins, phenolic compounds and other organic acids which are also absorbed on the ionic exchange resin and eluted with the anthocyanin. When sulfur dioxide is added to anthocyanin it only reacts with the monomeric anthocyanin pigment and forms a uncharged anthocyanin sulfur dioxide complex. When an acidified alcohol is added to anthocyanin it mainly facilitates the extraction of the anothocyanic pigment from its source. Adding an acidified alcohol to an anthocyanin-sulfur dioxide complex simply breaks the anthocyanin-sulfur dioxide bond leaving a charged anthocyanin pigment which can be adsorbed on an ion exchange resin. The present invention on the other hand forms an uncharged anthocyanin-(HSO.sub.3) complex which is adsorbed on a non-ionic exchange resin. Although, Phenolic compounds and tannins are adsorbed on this resin, the addition of acidified alcohol to this resin, selectively breaks the anthocyanin-(HSO.sub.3) complex, thus eluting essentially purified monomeric anthocyanic pigments.
It is an object of the present invention to provide a novel method of obtaining monomeric anthocyanin colorant having a high color strength. It is a further object to provide a process for concentrating anthocyanin colorant by removing sugars, organic acids, polymerized anthocyanin pigment and other water-soluble non-pigmented material from the pigment material in grape pomace, thus concentrating the pigment. It is a further object to provide an anthocyanin colorant of high color strength and to provide food products colored thereby.